The site of Diring Yuriakh in central Siberia has been dated to ca. 300,000 years ago, suggesting that hominids may have settled the area 270,000 years earlier than previously thought, according to a report in Science. A team led by Michael R. Waters of Texas A&M University used thermoluminescence dating to estimate the ages of layers above and below one containing stone flakes and a few rocks resembling simple tools known as unifacial choppers. These dates provided a range of 260,000 to 370,000 years for the deposition of the stones. Many experts in chronometric dating methods find the work solid, though Jack Rink of McMaster University in Ontario was cited in Science as saying that he would like to see them verified by another method.

Debate about the site centers on whether the proposed artifacts are in fact manmade. Though Waters and his team say they are, and present a variety of arguments to support their case, not all scholars are convinced. Paleoanthropologist Richard Klein of Stanford University, who has seen some of the pieces, says they may instead have been shaped by natural processes such as river flow or frost heaving that can occasionally flake stones. The issue depends in part on the number of nonartifactual rocks from which the flaked pieces were selected. Though such a number is not available, it must be large since the original excavation covered 1.5 square miles. Microscopic examination of the stones' surfaces could in theory determine whether they were tools by looking for tiny scars left by the materials they were used to cut, but Klein doubts this would work in practice because the surfaces are very abraded and few use traces are likely to have survived.

Diring Yuriakh was discovered in 1982 by Russian archaeologist Yuri Mochanov, who has argued that it is 1.8 to 3.2 million years old.